Significant Accounting Policies (Details) - USD ($) $ in Thousands				3 Months Ended		12 Months Ended
	Jun. 09, 2022	Oct. 30, 2020	Aug. 03, 2020	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2024
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income				$ 184,615	$ 202,447
Qualifying assets				83.96%		83.78%
Total assets at fair value are in non-accrual status				0.50%		0.30%
Time dividends have remained unpaid				2 years
Control Investments
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income				$ 72,092		$ 280,537
Control Investments | Previously Reported
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income					73,243
Non-Control/ Non-Affiliate Investments | Previously Reported
Investments in and Advances to Affiliates, Activity [Line Items]
Interest Income					$ 112,517
5.50% Preferred Stock
Temporary Equity [Line Items]
Dividend rate			5.50%	5.50%	5.50%
Dividend rate	5.50%	5.50%	5.50%	5.50%	5.50%
6.50% Preferred Stock
Temporary Equity [Line Items]
Dividend rate		6.50%	6.50%	6.50%	6.50%
Dividend rate			6.50%	6.50%	6.50%
5.35% Series A Preferred Stock
Temporary Equity [Line Items]
Dividend rate				5.35%